World War II: Battle of Eniwetok

Following the U.S. victory at Tarawa in November 1943, Allied forces pressed forward with their island-hopping campaign by advancing against Japanese positions in the Marshall Islands. Part of the "Eastern Mandates," the Marshalls had been a German possession and were given to Japan after World War I. Though held as part of the outer ring of Japanese territory, planners in Tokyo decided after the loss of the Solomons and New Guinea that the chain was expendable. With this in mind, what forces were available were moved to the area to make the islands' capture as costly as possible.

Background

Commanded by Rear Admiral Monzo Akiyama, Japanese troops in the Marshalls consisted of the 6th Base Force, which originally numbered around 8,100 men and 110 aircraft. While a relatively large force, Akiyama's strength was diluted by the requirement to spread his command over all of the Marshalls. Also, much of Akiyama's command included labor/construction details or naval troops with little infantry training. As a result, Akiyama could only muster around 4,000 effective. Anticipating that the assault would strike one of the outlying islands first, he positioned the majority of his men on Jaluit, Millie, Maloelap, and Wotje.

American Plans

In November 1943, American airstrikes commenced eliminating Akiyama's airpower, destroying 71 aircraft. These were partially replaced by reinforcements brought in from Truk during the following weeks. On the Allied side, Admiral Chester Nimitz initially planned a series of attacks on the outer islands of the Marshalls, but upon receiving word of Japanese troop dispositions through ULTRA radio intercepts elected to change his approach.

Rather than assault where Akiyama's defenses were strongest, Nimitz ordered his forces to move against Kwajalein Atoll in the central Marshalls. Attacking on Jan. 31, 1944, Rear Admiral Richmond K. Turner's 5th Amphibious Force landed elements of Major General Holland M. Smith's V Amphibious Corps on the islands that formed the atoll. With support from Rear Admiral Marc A. Mitscher's carriers, American forces secured Kwajalein in four days.

Shifting Timeline

With the rapid capture of Kwajalein, Nimitz flew out from Pearl Harbor to meet with his commanders. The resulting discussions led to the decision to immediately move against Eniwetok Atoll, 330 miles to the northwest. Initially scheduled for May, the invasion of Eniwetok was assigned to Brigadier General Thomas E. Watson's command which was centered on the 22nd Marines and 106th Infantry Regiment. Advanced to mid-February, plans for capturing the atoll called for landings on three of its islands: Engebi, Eniwetok, and Parry. 

Key Events

Arriving off Engebi on Feb. 17, 1944, Allied warships commenced bombarding the island while elements of the 2nd Separate Pack Howitzer Battalion and the 104th Field Artillery Battalion landed on adjacent islets.

Capture of Engebi

The next morning the 1st and 2nd Battalions from Colonel John T. Walker's 22nd Marines began landing and moved ashore. Encountering the enemy, they found that the Japanese had centered their defense in a palm grove in the island's center. Fighting from spider holes (concealed foxholes) and the underbrush, the Japanese proved difficult to locate. Supported by artillery which had landed the day before, the Marines succeeded in overwhelming the defenders and secured the island by that afternoon. The next day was spent eliminating the remaining pockets of resistance.

Focus on Eniwetok

With Engebi taken, Watson shifted his focus to Eniwetok. Following a brief naval bombardment on February 19, the 1st and 3rd Battalions of the 106th Infantry moved towards the beach. Encountering fierce resistance, the 106th was also hampered by a steep bluff that blocked their advance inland. This also caused traffic issues on the beach, as AmTracs were unable to move forward.

Concerned about the delays, Watson instructed the 106th's commander, Colonel Russell G. Ayers, to press his attack. Fighting from spider holes and from behind log barriers, the Japanese continued to slow Ayers' men. To quickly secure the island, Watson directed the 3rd Battalion of the 22nd Marines to land early that afternoon. Hitting the beach, the Marines were quickly engaged and soon bore the brunt of the fight to secure the southern part of Eniwetok.

After pausing for the night, they renewed their attack in the morning, and eliminated enemy resistance later in the day. In the northern part of the island, the Japanese continued to hold out and were not overcome until late on February 21.

Taking Parry

The extended fight for Eniwetok compelled Watson to alter his plans for the attack on Parry. For this part of the operation, the 1st and 2nd Battalions of the 22nd Marines were withdrawn from Engebi, while the 3rd Battalion was pulled from Eniwetok. 

To expedite Parry's capture, the island was subjected to an intense naval bombardment on February 22. Led by the battleships USS Pennsylvania (BB-38) and USS Tennessee (BB-43), Allied warships hit Parry with over 900 tons of shells. At 9 a.m., the 1st and 2nd Battalions moved ashore behind a creeping bombardment. Encountering similar defenses to Engebi and Eniwetok, the Marines steadily advanced and secured the island around 7:30 p.m. Sporadic fighting lasted through the following day as the last Japanese holdouts were eliminated.

Aftermath

The fighting for Eniwetok Atoll saw Allied forces sustain 348 killed and 866 wounded while the Japanese garrison incurred losses of 3,380 killed and 105 captured. With key objectives in the Marshalls secured, Nimitz's forces briefly shifted south to aid General Douglas MacArthur's campaign in New Guinea. This done, plans moved forward for continuing the campaign in the Central Pacific with landings in the Marianas. Advancing in June, Allied forces won victories at Saipan, Guam, and Tinian as well as a decisive naval triumph at the Philippine Sea.